We show that bundles of carbon nanotubes can be coiled into ring structures by controlling the contraction of their polymer shells. With the robust carbon nanotubes, we demonstrate their reversible transformation between circular and compressed rings in a colloid.
Structurally, stilbene and azobenzene molecules exist in closed and open cis and trans forms, which are able to transform into each other under the influence of light (photoisomerization). To accurately simulate the photoisomerization processes, one must go beyond ground-state (Born-Oppenheimer) calculations and include nonadiabatic coupling between the electronic and vibrational states. We have successfully implemented nonadiabatic couplings and a surface-hopping algorithm within a density functional theory approach that utilizes local orbitals. We demonstrate the effectiveness of our approach by performing molecular dynamics simulations of the cis-trans photoisomerization in both azobenzene and stilbene upon excitation into the S1 state. By generating an ensemble of trajectories, we can gather characteristic transformation times and quantum yields that we will discuss and compare with ultrafast spectroscopic experiments.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.